Notice of demand under section 156 requires mandatory service before recovery and deems certain intimations as demand. Notice of demand under section 156 obliges the Assessing Officer to serve a specified demand for tax, interest, penalty or other sums payable consequent to an order; intimations under sections 143(1) or 200A are deemed notices of demand. For assessment years from 01.04.2021, tax or interest on income from specified securities or sweat equity allotted or transferred by a current employer that is an eligible start-up is payable within fourteen days of the earliest of forty eight months after the assessment year, sale of the security, or cessation of employment. Recovery is invalid without prior service of the notice.